Inspired by: Knit Lighting – Joachim Froment
Trade fairs provide CEAD with the perfect opportunity to show what our large scale additive manufacturing machines are capable of. Last May, our engineers designed and printed a comfortable armchair. For Formnext 2022, we aimed to design more 3D printed interior elements.
Our Technical Sales Engineers partnered up with material designer Techmer PM in order to come up with an innovative design. The printing process normally requires fibers to improve the printing process, since both output and stability profit from the use of fibers. However, fibers also create opacity, which gets in the way of the transparency of the material. Techmer PM provided a material which is highly transparent, strong, and offers stability and good layer adhesion without the need of fiber-reinforcement. This case study elaborates on the printing process.
Design of the transparent additive manufactured lamps
The lamps are parametrically generated. Parametric refers to the creation of shapes based on programming code or mathematical formulas. The code that has been written divided the length of the 120 cm long lamp in different sections, also referred to as ‘plains’.
Subsequently, the code is used to define circles for each plain. These circles can be given any size, quantity and distance from the center point of the lamp. In the plain of each circle, additional circles have been defined to form a unique shape. We were able to rotate these circles relative to the center and to each other.
These sections were combined using a ‘loft’ to create the final shape. resulting in the distinctive shapes that are visible in the photograph. A loft creates a 3D solid or surface in the space between several cross sections. The cross sections define the shape of the resulting solid or surface.
The design of the lamp was inspired by natural forms, but created using mathematical formulas. Inspiration was drawn from the pancake rocks in Punakaiki, New Zealand and the lamps have been described as “art nouveau of the 21st century”.
LED fluorescent light tubes were implemented to provide illumination of the lamp, maximizing light output with as little energy as possible.
Transparent fiber-less PETG
The transparentness of the lamp provides a characteristic aspect for the lamps. The material provided by Techmer PM, HiFill® PETG 1704 3DP, enables this distinctive feature. Generally speaking, the material used for large scale additive manufacturing contains some sort of (glass, carbon or natural) fiber. This fiber is added to provide a better layer adhesion, improving the ease of use. While fiber adds strength, it also adds a visual aspect to the material. With transparent PETG, any fiber inside the material will be visible.
This is why Techmer PM developed the fiberless HiFill® PETG 1704 3DP, resulting in a highly transparent output. While the material does not contain fibers or other reinforcements, it still provides a solid and reliable material for additive manufacturing.
The printing process
The possibility to print transparent and reliable PETG that Techmer PM’s material provided is unique. The tricky part of transparent printing is that you need to make sure that the entire system is clean. Any left material from previous prints will be visible in the product, even more than when printing, for example, white material.
The printing process per lamp consisted of about 8-10 hours and used about 3 kilograms. The limiting factor for speed in this case was layer time. The layer on which the new layer was placed needed to be warm enough for adhesion, yet cool enough to provide the strength needed. The material was printed at 235 degrees Celsius, on a CEAD E25 robot extruder
For aesthetic reasons, CEAD chose to make the layer height as large as possible, in this case three millimeters. This was done in order to represent the pancake rocks and to emphasize the layers created by the additive manufacturing process. A lower layer height, providing a more delicate end result, was also possible. The layer width is 6 millimeters, resulting in a layer ratio of 1:2 (height/width).
Advantages of using additive manufacturing
The design of the lamps took into account the capabilities of the additive manufacturing technology. In this case, a plainer printing strategy was chosen. Because of the nature of additive manufacturing, the angles relative to the previous layer cannot exceed 45 degrees. We also refer to this angle as overhang.
The main advantage of additive manufacturing for this production was that you can start prototyping directly from a CAD model. No extra steps are needed, which saves time, materials and thus production costs as well. Additionally, it is fairly simple to edit the existing design. Simply alter a few parameters in the generator and new lamp shapes will emerge.
About Techmer PM
Founded in 1981, Clinton, Tenn.-based Techmer PM LLC, is a materials design company that specializes in modifying and fine-tuning the properties of technical polymers. The company thrives on partnering and collaborating with plastics processors, fabricators, designers, specifiers, and brand owners. Drawing on a broad portfolio of resins –– from polyolefins to PEEK –– Techmer PM helps manufacturers enhance product function and appearance in scores of end-use markets.
The award-winning firm operates seven North American plants and has extensive expertise in virtually every plastics- and fiber-related process, from additive manufacturing and blown film to nonwovens, injection molding, and sheet extrusion. Techmer PM is a six-time Plastics News honoree on its “Best Places to Work” list. Learn more by visiting www.techmerpm.com.
Techmer PM on the case study:
“We’re excited to see CEAD’s success using our HiFill® PETG 1704 3DP material and looking forward to continued partnership with the CEAD team. Our PETG materials are excellent for aesthetic or high-clarity applications such as this lamp. PETG is also a viable ABS replacement in a variety of room-temperature applications. PETG does not off-gas or smoke like ABS does during printing and has a lower degree of warpage relative to comparable filled and unfilled ABS grades. It is also highly colorable and can be formulated with various visual effects.” – Anthony Fiorini, Business Development Manager – Additive Manufacturing, Techmer PM.